its easy just look for the dicks, and you'll defo be able to notice the pussys.
http://www.concept420.com/marijuana_difference_between_male_and_female.htm
First signs of sex should appear within 1-2 weeks of flowering.
JJD
Preflower.Actually that is Not flowering.
Its a stage in Veg called Preflower.
Its a sign of a plant that has reached Sexual Maturity.
So the first sign of Sex is when the plants become Sexually Mature during the Veg stage.
And its known as Preflower.